Merge pull request #220 from erizocosmico/fix/avoid-missing-ref-hashes

gitbase: skip hash references that do not point to commits

Author: erizocosmico

iterator.go

@@ -5,6 +5,7 @@ import (
 	"path/filepath"
 	"strings"
 
+	errors "gopkg.in/src-d/go-errors.v1"
 	git "gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/plumbing/filemode"
@@ -786,12 +787,21 @@ func (i *refCommitsIter) Advance() error {
 
 		if i.commits == nil {
 			err := i.refs.Advance()
-			if err == io.EOF {
-				i.refs = nil
-				return io.EOF
+			if err != nil {
+				if err == io.EOF {
+					i.refs = nil
+					return io.EOF
+				}
+
+				return err
 			}
 
+			_, err = resolveCommit(i.repo, i.refs.Ref().Hash())
 			if err != nil {
+				if errInvalidCommit.Is(err) {
+					continue
+				}
+
 				return err
 			}
 
@@ -882,17 +892,20 @@ func (i *refHeadCommitsIter) Advance() error {
 		}
 
 		err := i.refs.Advance()
-		if err == io.EOF {
-			i.refs = nil
-			return io.EOF
-		}
-
 		if err != nil {
+			if err == io.EOF {
+				i.refs = nil
+				return io.EOF
+			}
+
 			return err
 		}
 
-		i.commit, err = i.repo.CommitObject(i.refs.Ref().Hash())
+		i.commit, err = resolveCommit(i.repo, i.refs.Ref().Hash())
 		if err != nil {
+			if errInvalidCommit.Is(err) {
+				continue
+			}
 			return err
 		}
 
@@ -1591,3 +1604,21 @@ func evalFilters(ctx *sql.Context, row sql.Row, filters sql.Expression) (bool, e
 
 	return v.(bool), nil
 }
+
+var errInvalidCommit = errors.NewKind("invalid commit of type: %T")
+
+func resolveCommit(repo *git.Repository, hash plumbing.Hash) (*object.Commit, error) {
+	obj, err := repo.Object(plumbing.AnyObject, hash)
+	if err != nil {
+		return nil, err
+	}
+
+	switch obj := obj.(type) {
+	case *object.Commit:
+		return obj, nil
+	case *object.Tag:
+		return resolveCommit(repo, obj.Target)
+	default:
+		return nil, errInvalidCommit.New(obj)
+	}
+}